SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a101938dd18b8bf63e2784f3b8383d9a25dfea62e349c97c678cc80edbf178d2' 
  AND token = 'bznlYppQLyzR0/F5oCMZg/8YYZPjhaaOLsFGghfuJvw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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