SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83f096c0159b77b9668b046220e55462c968fe3cb4441a6de2a1f3d32a3288d5' 
  AND token = '5SpPp3wD6aRaibp2Yy6uv94nlsYjPg56aKzeivMpJls=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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