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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '6994ca18dfcbdb3853d8f095d07aea609a81228f61ca1ff747bc5d32a0518122' 
  AND token = '7FdKQk0NkJPiRARrAoqWxZPUWNT+K978cup8GstA6kE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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