SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6e747cb92526a2bd77619f3dfd4aff6dd2031a374a96f0de55c1a5b5d2baa64a' 
  AND token = 'rQ6WoHQgaYpPBnKDudUS7tVu8dD3OQHbhuh+0ev/DxA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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