SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ea1fdda3b9f7b4b34cbfe267e2cbadd6377c088d31727020bf638eb0b60645c' 
  AND token = 'pSlgC90ziX4HGkUqonB2nJwATYr1YRmjJWNAkJGB2pI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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