SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6bb06ff2078ff1751624296e77ca3ff43658efc73749c28e049d0b7777ab96c0' 
  AND token = 'sbovMMgrgQnD1Jm/hn0s9+LPgzJNWzi8WyKpFWoVJOQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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