SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3366b3ba682994a2972103d1561fddc1ce6aa677446ea2eb93b38bf317b396f1' 
  AND token = 'UDuzIaLq4+iovhbuxZ7IhqvHVXe7jjOBryC241bvpog=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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