SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4bc714df74039f67985cddeacf92dc59f4bdfe940d4ccd8f24d0c40845ebe47' 
  AND token = 'iNCHekZDtt/0Rs7+nmweyRc/y9c4PTWMwpuiJqNkk5Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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