SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '80029823e1c93b13706854997a3a6775c050986cb5f4a07e1381d07c621979f5' 
  AND token = 'apkjRgO+KEp689FAL6rEqn4YEvakgUcqneUhuOT6tM4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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