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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad3878bb8e1b89d4a5027fb60bc19cb283eabeb5c8eb3e92c2540c74bf2c4a8b' 
  AND token = 'Pe7JnsROGXw5F/xWISFaekWmzhvLcCzITtB8Biy2vYs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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