SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '92304f808043f069723858e906eb2e33a3db5df6eb116290548b24521559102d' 
  AND token = 'NzrAlJX3gZZSoIsWqvQC4wLaR38lCOlUQLzktCyZfzo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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