SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7df9b420544ec02e1e92ed69aa9fae0cfcf08c1cf315eb0c9b01c04e2a407474' 
  AND token = 'KlklimTx91UU152axSpxAmnrbPH50RFH8DJvODAf8jY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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