SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5de4bd0b4f7f1a11d2f07a4f9b4c81fcbee9c2b90f7502d3b4d4b31625423ed' 
  AND token = 'gL0tdJTfBuLRN+l4YzTLCCUt1HdauLoCZyVyMeoPuVY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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