SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e52aea1c8f8c5b5a19a992cf7289be2211783c643d982b7ec0885f552415ec91' 
  AND token = 'FuSDnaskJW+06t3G/LnxKctYrKuwIVUTn6rbs55FWxY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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