SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a66142385ea5e4eab5d5a01eca8b894be3d2be37e7696cd8454383429eb50ac5' 
  AND token = 'HLNJjoA489pdU8CqaOtutmaq/Qd92QKoEDeBGo6qGOA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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