SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7d46558476075d4c0618d663c5717623d21b1827b4237646f8ac1cf37b6d3440' 
  AND token = 'ADKpNVGTqmh7RK4hHFoBv7UijZYnyV9BDoM6u698CSo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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