SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c7b5991f4939453cbec62fa7f09d9a8c64453fcc3c6fa1a0eebe59011127a50' 
  AND token = 'HrYvRj8Z2Fjx/LRAY5oL703JkXqyZGzPgqqIUQdHF00=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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