SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4e62ea21d53d17c85605ec674f7614741b758bf39d1f527b13b2d6cb6cecb503' 
  AND token = 'M8piyC09QezAJlCWEJ3dL4VVZ+qKEDup1/Wh/Dh92fc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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