SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52cd1d8b3310bd0875a471bf2db02afa631b4466b67a5c14abc58724f0e9091b' 
  AND token = 'qRDPxQLOuGUjv6iY1kjcGSYeN28xd4hcWtXYx9XKsCw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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