SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b13fdb81f3685ed118fa6d115925e18d0b5736129e02c71889f987c009b44ff' 
  AND token = 'FnpBSggXIkhzKNwxDXEbq4YM7UDQ/sNHofQptIrkmKU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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