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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '83c7e1c1ae6ebc0478fcb5c9e47c324174071d081f7838fef9aa28fea281746e' 
  AND token = '/Cxgbou5ktrCVmLGzCvMvmauz07Q8SHRDiJcsA+z2YI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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