SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4397770c046fbd317e1b4b84866e516ddf025f1662b817e5443ef2e12dad264d' 
  AND token = 'wX0rnKX1sTfijZpDLIZQLNP1c+fKSsCMqObym7oA1D8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}