SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a4bbbadcef0d923bb85a73b7bf983a1734412216289704cb8a3cf3f5995f97a' 
  AND token = 'muoctWNY87tfaDLnCwcr/eoV9ZgCFMVFZw5M3HirSLE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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