SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f26be1f9c2825c010a61fd267ec0bef65c84eb6fe43b514767d107d231c9af32' 
  AND token = '8pxhjkgxhw1JdsLDyvMTAOyOBAj5NOFlo+uk7OZOrPw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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