SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3029aaea1cf2d13bc402a6af6e1cb683ea3f54afa43baa0f3e09f9496def2d05' 
  AND token = '3VCTDefGa4DCP7Li6hnsaS4gHRPiMeYL9S477FyosSY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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