SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7963bca1c76457f212cb09a6ec298d31fb519cd8e5caf439d0b2756bcdead4c0' 
  AND token = 'IrwVSkoVQXPZja6tUCebVaAcO2liejrfAl/vilGsdjM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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