SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '207421541434575b4cde8e7551b225c4e184cbc644508a7c0024d05de44c07e7' 
  AND token = 'iBckvoZsughMlsNTYYVKSLfapSG6nsDDDhaY4AMAnIY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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