SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b237fed474ce95335aed4f94a495d3e3503b0967db98fd9e2ca6ac667acb73a0' 
  AND token = 'QTA+M5O6vpVljBk2JPFGpEnUoitoi2jIG/JPWtonPHc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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