SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f25e2f4c968276bcf8c43a9899275704f104a389bac604535e0d3191695b91e4' 
  AND token = 'wE9ejoZkgJ0CBy3uShm/5QOlndUcNI/JjtQJSzTLvck=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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