SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55eeb5aee02f7bfb2e59209b96e2a8646f19b983d5aff5d8334f57bedbdd6747' 
  AND token = 'Zf+e4XKsZnG0dbfJU8BtCEERdjs/0/kELwHI/d5AMCk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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