SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd71824994ca63f9cb61927393babf672e116fa6d5d0c3c8d44ca98f4180d2f5' 
  AND token = 'jrInMP8PjhZC+ThFRsnMou7Satp/mecxqqbIv8AeRgE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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