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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'a010fbb1712d6eb2169f27bcb2f6eb8bf45e66c9033929d191ec3e94b89f746b' 
  AND token = 'gM508I1heeoQ811sHxWBgiR3Aq9JFiELJzQWeI/DfUY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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