SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19989e99e897b112cce00626ec633eb45bd3907ba8eb5f243aebb9eafc2fb7aa' 
  AND token = 'y3Oc4jEH5K60FlhYBQOCdqkjMjNlWGbPem+SHSF4fdY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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