SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'edd3916748a9797054e227ba8d99470c400b505ee1e1b8565d01f8095cb86597' 
  AND token = 'acdy41fHnFW0U8vqjtolcCHACJ7LCbWxRDrYokUg5J8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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