SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20c0aa29c308880b5916c586f6ad6263d8bd28418c380e2295ae6f14176367d6' 
  AND token = 'nUbk/6jdzzP8+vYJGX7vmyZrnHIakGmJugYm7SLVk8I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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