SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '501c29f47f46d6ceadd34f9a2a67ce870a3a3378e95ecd1b5c67c62fbd6bf687' 
  AND token = 'UdfroJgpq8ipKTaRKyJsCpGlZ4pJ1OCJGHYcj87zs+I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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