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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '99b5edc4b50c686d1c1346ee6cc8009c0e0ce3590fe124f1e3908dd6bd8d4461' 
  AND token = 'FMrEL3uYzuh8V0Lo1XZPa/DPSyrfuOtCxmMBVjFgwfc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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