SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce8f9b94a08fe10f0afad1b44e4cce51d0715b1e448a3665e1eddcd82ee36e95' 
  AND token = 'EwMNhiABi4dfSP/EKxpJ2vq+ze6lKs0b0fIdNTHeDaY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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