SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2e281b68965648d86eadcc1e046dc37af807dfe0091dc7536e6dec4cf376bd2f' 
  AND token = 'CuuTwQeM+JVltlTtt1Jru1z3iq/xlmq9v/rqpNmuY2c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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