SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54338cbc0709346bb7501727bed5dc1d6387357009514e5bea98770fb0946440' 
  AND token = 'XD10cGbWr/k6ExBJ0dRSxybQp/vJIYJQaZnmSP8HV3A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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