SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d9f5cd29e4e5a0ab1a8239e22738d74e138962d51aa8152cabb7a3b4cbe24ad' 
  AND token = 'sn1lQCzxH4cu2BYSZOU4TpKd/W3AbqFEsMWfIeVFp7w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}