SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df7cff71d1f0d4385eff9ba98363301acd0b7afc3eb1ca50591925501329aca3' 
  AND token = 'dYsvbVRebvv3znNe3OMvh8jOCFvsf12wn2VPCgJ0r/0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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