SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c8bb7173f3d0beee22008128cc951236f5085720b74102576fa3faa918d9bb8' 
  AND token = 'BPcY/QPYfuTmdwxDH3YMN23CiCff7EXVleWrOyJz5jo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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