SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f123000f68ab3fad340954537dee487f387532673a3e9dae7a15a7252b00fd3' 
  AND token = 'CQbtPWjpZ0GcHvhqD5Ww4yvY96+ZNYNTPJjxl87ADX8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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