SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af5158bb2ebdb60333644fb2522cf913fb9f5a44a8b47c3560287b6cd1816b21' 
  AND token = 'TWmmczhge6/I9PEipLutD4FIUFo+LFtTzOSxLoBGOQw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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