SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a3161e458b67df7013187ff625346e54e4f18abe7af1c0d1f069ede7f632ad3a' 
  AND token = '/E4toc6QEr3XVu2SbVWPwNQGnDuUEv4cQuRDr1UK6xw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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