SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3dac559684a00c85f83c011adcfba6d09b6a2b42f9bb883956eb8324d7c47c68' 
  AND token = 'IK0/5JhblcNSaKqwBjupDAlTI0JLvUY48CjSwPiZYIo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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