SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd5e96100e9fa65785da7664f6ae2581e46b8ef0881ff74e6a3bf371be6796db2' 
  AND token = 'GUrEQCsD28ktXZuZKKFXHCzqToZEDh+SgyYPQJvWljc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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