SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '958917622742fcae2c06caff6dd6b221a60119cfe32c34ccc1d5c925aa0d07e9' 
  AND token = 'B28UnUjniudDV5RpdRFbve6cpp3/0rxqHiNPMKa1F1A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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