SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c9fd0d9106dbcd84c8380e7945c51677e4028ba0b6f6240914094a3be184b8fc' 
  AND token = 'xniHkzAsdASGqO6fx18dJNPMTq4da1Yl2pkVwGXXK8s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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