SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e9bad8be655ccc99aa3e5221cb9ce0f8cac13b2ad01342c9d5d46e6beeefa60' 
  AND token = 'idUngYf4kVTbI70zdXfTOndNVNI9fl2UvVqycndDuQY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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