SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '823cbf115ebda46e902be8ef29a87b891724f56e1eb30ee5b6b29bcbd8fed6e7' 
  AND token = 'Ff4lR6KpN4IfDLPTrU7nDfmmei9acV9uoDcXKm3dEG4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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