SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd5f81320baf64b15b39e0a3e169c54cf88de116272356b4b7d5b272be19764ce' 
  AND token = '6FIJ8dU7qlwZEPNdOtPqENwSQU+845c8Bf1Ph2aDt90=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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