SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '13e0cdbb9802284fa8ee86e104cd9f295b8d4bb1877baaa21b9d8609ea467310' 
  AND token = 'HImPbe5DDU73KUGqdyVmWlVyoyRs+CriKLDkKNd7ZEA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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