SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e385c714ae4f915b835d9f276e2c9ef8dce36f09086968eaf0132d0f35d3f340' 
  AND token = 'ZdEIov+JDgQGILbqrc0raUzAvV5+LpoVn+cvwQaDj8g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}