SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56c50da9adf4f953c3d7ae1a82822e80d86b3855188867130d211d31cd267759' 
  AND token = 'LCWA9QWA+QcoNtBLmi/Tbr2rwyJpHLEHo6fWoDtlSiU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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