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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'c33899334e47b241b5dc3ee8b22ccad1dd9638dbc3f3ddfbd25fd15bd17ed9bb' 
  AND token = 'mr5BMEaKVGi6S94mdzsEpZTgKRR4V5h2J+/8gN0V2l4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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