SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3bd2e63dba799a074f6f43a46eb259a8aca53359dde9fab481a8fb263ef196b8' 
  AND token = 'pMfyywLg03nH5NsG80JqZqVzjnYRJig+9nXKPHdYwcI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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