SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f1c13d5c2bbb99d424ef10307b8e62002ba4441e141c43baa3fc0929fa7f6c3' 
  AND token = 'NZLA3uI/mjmJSC1ms3Iz4dOAcEFjVYhZKqDqQzH2/qM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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