SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'dc0a3b9220ba3b661d5a029301168d5f9788ea95f9bca9a15d41da644a149083' 
  AND token = 'Ex3CRz0OKUyrnOnP+NybNcoQPjynEu8gslI9LwEl6XY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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