SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'acdfec67acc5b04f3847828d100230525519b1573abf24b2bd4675ac8956654a' 
  AND token = '9Pop6DdjukcHBOQwKPjNEK+3kluuAv0xOAEVztBUxxI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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