SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68a9bdddfb3aec6d5b2cedd31795a98639f223b937c9ca443aabd811a5a3ec00' 
  AND token = 'XXskRqEK6ENvbjh5e0VOR2VFh/ezkFNDZerHAqwN/10=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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