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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '63257cbf9f18838d9c148fea9a7167e0d4cf6e732ce6b209147ebe45c341f2b2' 
  AND token = 'rAs5e5ItsclrEtnx5IiuJ/qczaM5pLhLhZUmEGaW4pw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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