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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31ec086535a71e07b3752b35be43d9b68e70400b9dc253ab3b7c4066ac9797e5' 
  AND token = '4XMTjxvcs3YbL6Y7PXpm3XEGwGljDWHErj0V0h4xCRs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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