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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb32adba95763453c93b8521f9f8f8df270fc2ad7991d6e4ccbe84c9df7df438' 
  AND token = 'nZ1tmFSJE7FVZ8OBNQrt500M2AtgH3iOUq7KHSH7Rb8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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