SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81d13d053acb7d79f68dad937a9f53fb0b7754e8bd4cbd95c3dd5265a3e5926e' 
  AND token = 'LiEp8ZsKGb2X+Bklhpvlak/e3wC3i6YAMZtzAuHVCUM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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