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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '9d0b7867e03ded2ed92a8d9947ca743e50596a23e0e1dddfcbfe8c59cba9aced' 
  AND token = '6oixkSCSKtqYhTgxLYQZHBt7o7NDZeYv1UacYCfnHVw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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