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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'd811e0ad9eec7d50eebc4d173efe192c9fc0a4c5c4fd9fa82f959414c43e4980' 
  AND token = 'ayWYdbRtg2rc6FcJabACoY1y2HeiJ/ELuWT+FT6O/Tk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}