SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3714f6d6f8337f783c2fb35809ebfcd1601cd39378278edb6e4a6d253b92f700' 
  AND token = 'cpk4LhIdazEQ/YY5b4vHZCgWj+kmL7s25WF2RC0DcvY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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