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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '2d544444d859c518ce86173410b763c8f7f38345598119eebfde8e4fc55133fb' 
  AND token = 'hmw571QNkThcN453fkCmdv+KxEGwT7M3XSyYCAoaan0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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