SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a6e05c31f5448111692b2dd423af7b47a931198389e1ba1fdafc53f28084f725' 
  AND token = '7fCTT5KUQ2ferwzjW+H021PIHuub+Gu2lY9vm7HYnN8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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