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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '76ed704455c4f195ac7220e1ffaee33e98e2b32cfc9a59f65114cf2dbc2e54c9' 
  AND token = 'l2+6iCgh+h3kwoHj9mIS2+yB0RNoff7gdnOYrT2L+kU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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