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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'c0fd9706ebfeda0037e33eb11e00a104b7ce1d4382ed9c5f58daab920b8cb4e1' 
  AND token = 'X66jCGP7nQs1S03wO5wz0CrtHPk5kimd/oZGr6+lEMQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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