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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e700de455da41db14f53727a099ec72ace3e09fd476d892c92ef4727e32a27b0' 
  AND token = '0/MDPZJHss6RjVokPGMUpBeugJ3rMofWEaDJX+np43A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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