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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '78286e559d646bd3b873c75935d81bed8e2653ba7d764fb54f7da71e706d76f2' 
  AND token = 'Czyb0ZXtY2UXTM2/HMo5eQ1D4M8bx5TPzYp+v2LgTW0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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