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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '38b0be518f01cceba1deb73ce29ce2bf9bbb8d8ea09e9c75c9e4e568be75c5ac' 
  AND token = 'MRXjQfqlis37fcCwCHnBQMk8sLq/i3VlWPrihCzOiaA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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