SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a0482e3406649def30e5b38f968f1c86121d52371b4efc621735dd8e34bb34fd' 
  AND token = 'vpBvGGAXPpsYwGwzmU4C2vF59+Dq4KtzjlJVOBL0Eqw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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