SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b487d72091f23de1eb5be69beee2bef2d31fa922ea055da7753bdd3bd9c5ba5f' 
  AND token = 'mbiCFOarExYpBeUeV9mHXKHPjsl6hutHAeKe+1LmO5k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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