SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e79913c99799be7031fa85f5045703830304c9c6b530567cf6385e9feac70bed' 
  AND token = 'aZ/GZBbrsmXIUPmx2WvCTzw57ZGbGPQwWGRAAzFq/0s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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