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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fd54ae3bc3186292e5c5e6c0c84ed4c1b5a6e7e480ae3ccbd66e6fe944d18227' 
  AND token = 'e+7BPgVH3xXMGXDRu2MtQAFjUbOQZzoH1sGKvKcfdh8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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