SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '100f9f82ba11030203d3b711bf805359c933fd30466249b439e5ac064333d67f' 
  AND token = 'RVwT6liaH5Cfy1v3Cr9hiy49ybpPznNhYLTWbCoA2D8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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