SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0373291ad4944424210f692418fc79e2b87d15a1fd9c0eb9a777166561ff208c' 
  AND token = 'oYO/CIZXSPtnL8tqTKDea64hGnz3ipbAh9BaJkL4WTA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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