SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9caef55159d56f5e60920a4d7afe4212414a246f36d39c179f35077dc24fe017' 
  AND token = 'QgWGPPeSgeebIRYp7var7+3Oms8lg4Kp4sX2GHeM/vU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}