SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fbffcdcb80b0227f0f37a3d6fe2f189e69676dd599db0c55f3e391e5ad559282' 
  AND token = 'z90jUY+UJ/wYOUHhbcwB76G7UfLCskFzBhSYWwgF1hQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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