SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e78c11925340f79095c77f8041093ce21af8406677223cba5f17155d17273558' 
  AND token = 'Ur5+x/ZQ+PYaR6Qqge827Iv+/K4UZKEWYIqZyd1jmLs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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