SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9bf6fef55ee1246dba2774a939c006f990c79d2a953d60617e8769e589c1bda' 
  AND token = 'iYN/Qb/6PBP+sWqv7QQn+1qQx+A8nD+GP4/JviwHJgg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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