SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '04976836d4d7a3e073ea033ea1dd9193ed708e98f6e20f50d361a989b7e8fc2a' 
  AND token = 'r4zZlZ9tNjDjOzYICeF2YmML0sEgNAxVsTIvoQuKZl0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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