SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b616d9ede590b4806730a7346f9d893b0e69ef92c30a62174bced713e81334d3' 
  AND token = 'HRv9r6spBiURwcnBMPS+83Ij/K9SoAUQq96kUI1Oi84=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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