SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a5c4b05c3864460b00feeb1c108271674f4a51830b59dd75e7f8fa3842ab665' 
  AND token = 'M/hHUcwg3kKSGnXmHq6h1tx9Vh9HuVVG2U6GAy9KkRI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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