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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '8aa5cde91b9bc2817fe3195b86c6592b56319ce9106bd2b6154abcb1cbaec2e7' 
  AND token = 'VTAbZ38IBh2MUzMbUYvb8JGn64GBK2FCKLe78DV2fVU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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