SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53a045d1895e6bc063d5d94eac6109343d2ccb0fc4516d9b67ff515c12810305' 
  AND token = 'HvoO/hBMT3y0IwWgyvT1pACQ1okyWSBnCTV4+vEGCJY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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