SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c14b57e79f86a892292b2924889f56fd9d46b665ab3e4a3f6c1122372f4886d' 
  AND token = 'Kg3V2XEprVn/MuF43RKYsvccRWuaHPzTsAgJO459hH8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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