SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c3a5da69dac7890ccda530295cd38058c1a38e97d62fad38036013a1d1fb807' 
  AND token = 'usMCFT5YbXRypY1oLlo+/QoPPEJZdupyjxc83Lbmkzs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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