SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c751c69ce66e4361137895ebebe50ba8eedee813552e26983b1a1c5c2399ca7' 
  AND token = 'UoM/X3uIpxWnyHcwmcdK6OFFEkeukeSVyUDZlZJ8K+U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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