SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '10db928b717a9334ba04dcb6bfbde7eeeb502e8b69b2265761edb89edd3e0a21' 
  AND token = 'JkjiNclsm/bWEnDgasx3d0lbu/UVgSr3VMgcDOCwlj8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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