SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57a0cf375709ae4738fe0b2afe5f65aae30421f41752a4b946da04c2cbbb15d6' 
  AND token = '2aXyG1phDhTYJQXdJWnyhqnuWIcCrQJyisPvkMdLDs0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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