SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b13e777aaaac86e128849b1a7f55b234679a4f7a20056657ef395fa8e13c246a' 
  AND token = 'DrQeLvnz1fdpkK6Nx/fcNtpYNe03ZYuE31ma4bnXamo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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