SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd989dafaf0ad73ac14ed035f7f81147565d1be3ac962523d356262930d23498b' 
  AND token = '+n0i1cXSh4TkBIQnXB8Of684bUuiwclXTOZ1Wn7cpsk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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