SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5803f735b5da66cd9a3b4c7af9ba942024a18be5b6cba5200e722b4640959a38' 
  AND token = 'EBJYfo2rjRazpLlAKepcfsxYnz5hk3ItJPTIEKkboO4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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