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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '0d5cb90ba5dbe4e3df7bf5b98e4561d08712011f08a3fde77f33a33e35075dbf' 
  AND token = 'ljD9TX1GQ2rfAypeKdjdMlYF1l+noQ78FZQIfnqRpOw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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