SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e730f93898ea344b6dcd7d7628cce88014cdb306b1a916cbcf347accf032fbc' 
  AND token = 'iAjGQUvYHSDOl3kcnGUUcBaEAPN1jbHcUctFL0//RTY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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