SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'c523d0fb15ac08d026f5b16c653aff536038466e90fabad51b13b958ebd5db43' 
  AND token = 'mWLSCvjhn+HKm6AvUNeku0zjA55e7y4ImZGvO4lOkS8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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