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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af404ff2d609f8f1c2169638e434b355d11689fa9f70975c97efa59e759a58a3' 
  AND token = 'QGiCLc+9JAeSMeURCzDhSYbj61M8/5NH+TKGV9flrAs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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