SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '23ad0776a1bb906d8bbbebe7786e23a6557fced9cf890ea6879edb35a4060df8' 
  AND token = 'BYjnh9Xq+Kygg69mRaF5W/hWwYTslPWhl0mhRV3oDD4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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