SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1acbf3fb7686d30b3bc54e788cf3b17e018182fb0601c8c2cec21f19d4447fe8' 
  AND token = 'IN41li6bp1jtA9higqpZemtwaYhumEvtGI+gkVONTyY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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