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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '7f1c22d06e0943b6587d9c36950a81ae333a447ea9a619a87b7fa17ae064de84' 
  AND token = 'QXstWPECMh+AWileK8dcEkdZfRF6owuuDWdeAdrvVdI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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