SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f63cd541948861bb1eba574524b0594a1dab3a18b1cb24e3a63fa47dd86754af' 
  AND token = 'k5wXJuhsLGkl4YPz/8LGYo4k8Gk1xgPyYg6bXazAh/Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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